This invention relates generally to a fuel pressure regulator and more specifically to a fuel pressure regulator for a fuel injector system in an internal combustion engine.
Fuel injection systems for automotive engines commonly include electromagnetic fuel injectors that deliver fuel from a fuel rail to the engine inlet manifold adjacent the engine combustion chamber inlet ports. Such fuel injection systems ordinarily include a fuel pressure regulator to control the pressure of the fuel in the rail. In such a system, the pressure in the fuel rail is usually controlled to maintain a constant pressure difference across the injector (i.e. from the pressure in the fuel rail to the pressure in the manifold). The fuel pressure regulator is connected to the inlet manifold to sense the manifold pressure, and to the fuel rail to sense fuel pressure in the rail and to discharge excess fuel from the rail so the fuel pressure in the rail varies with the manifold pressure and is maintained at the desired difference above the manifold pressure.
Conventional fuel pressure regulators include a valve and a valve seat, both made of metal and including precisely machined and polished surfaces designed to contact each other to form a seal. The valve is biased into the closed position by a coil spring that may bias the valve laterally with respect to the seat. Lateral spring bias may cause the valve to seat improperly, causing leakage or other problems. Existing fuel pressure regulators, such as that disclosed in U.S. Pat. No. 4,756,289 to Rock et al. include a ball and socket arrangement to align the valve with the valve seat to provide the necessary rotational motion of the valve to permit alignment of the valve seating surface with the seating surface of the seat. This arrangement includes numerous parts that require high precision machining and polishing operations, as well as numerous assembly steps due to the relatively large number of parts.
One aspect of the present invention is a fuel pressure regulator for supplying fuel to the intake of an internal combustion engine at a substantially constant pressure. The fuel pressure regulator includes a housing defining a fuel chamber in fluid communication with a fluid inlet. The housing further includes a fuel outlet opening in fluid communication with the fuel chamber. The housing includes a seating surface around the outlet opening. A valve body is moveably disposed within the housing and moves between open and closed positions. The valve body contacts and seals against the seating surface and prevents fuel flow through the outlet opening when the valve body is in the closed position. The valve body is biased into the closed position, and includes an extension with at least a portion thereof disposed in the fuel outlet opening to guide the valve body.
Another aspect of the present invention is a fuel pressure regulator for supplying fuel at a substantially constant pressure. The fuel pressure regulator includes a housing having a fuel inlet and defining a fuel chamber in fluid communication with the fuel inlet. The housing also includes a fuel outlet in fluid communication with the fuel chamber, and a seating surface adjacent the fuel outlet. A valve body is disposed within the housing and is moveable between an opened position permitting fuel flow through the fuel chamber and a closed position preventing fuel flow through the fuel chamber. The valve body is normally biased into the closed position. The valve body includes a rigid molded polymer body portion and an elastomeric seal configured to engage the seating surface when the valve body is in the closed position.
Yet another aspect of the present invention is a fuel pressure regulator for supplying fuel at a substantially constant pressure. The fuel pressure regulator includes a housing having a fuel inlet and a fuel outlet and defining a seating surface. A valve body is moveably disposed within the housing and is moveable between an open position permitting fuel flow through the housing, and a closed position preventing fuel flow through the housing. The valve body includes a guide member, at least a portion of which is disposed in a selected one of the fuel inlet and the fuel outlet to guide the valve body. The valve body has a body portion made of a rigid material, and a seal that is made of a material that is soft relative to the body portion. The valve body is normally biased into the closed position and configured to shift to the open position when pressurized fuel is present in the inlet.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.